Back illuminated sensor with low crosstalk
First Claim
1. A back-illuminated image sensor, comprising:
- a sensor layer having a frontside and a backside opposite the frontside;
an insulating layer adjacent the backside;
a circuit layer adjacent the frontside;
a plurality of photodetectors of a first type conductivity for converting light incident on the backside into photo-generated charges, the photodetectors having a depletion region, wherein the plurality of photodetectors are disposed in the sensor layer adjacent the frontside;
a region of a second type conductivity formed in at least a portion of the sensor layer adjacent the frontside and connected to a voltage terminal for biasing the second type conductivity region at a predetermined voltage;
a well of the second type conductivity formed in the sensor layer adjacent the backside; and
trench isolations in the sensor layer starting at the frontside and extending beyond the depletion region of the photodetectors and to portions of the insulating laver, wherein the trench isolations include portions that do not extend to the insulating layer so as to connect the well at the backside between adjacent photodetectors; and
a lining of the second type conductivity lining the trench isolations, wherein the lining electrically connects the region of the second type conductivity adjacent the frontside with the well adjacent the backside.
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Accused Products
Abstract
A back-illuminated image sensor includes a sensor layer having a frontside and a backside opposite the frontside. An insulating layer is situated adjacent the backside and a circuit layer is adjacent the frontside. A plurality of photodetectors of a first type conductivity convert light incident on the backside into photo-generated charges. The photodetectors are disposed in the sensor layer adjacent the frontside. A region of a second type conductivity is formed in at least a portion of the sensor layer adjacent the frontside and is connected to a voltage terminal for biasing the second type conductivity region at a predetermined voltage. A well of the second type conductivity is formed in the sensor layer adjacent the backside. Trench isolations in the sensor layer start at the frontside and extend beyond the depletion region of the photodiodes.
46 Citations
13 Claims
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1. A back-illuminated image sensor, comprising:
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a sensor layer having a frontside and a backside opposite the frontside; an insulating layer adjacent the backside; a circuit layer adjacent the frontside; a plurality of photodetectors of a first type conductivity for converting light incident on the backside into photo-generated charges, the photodetectors having a depletion region, wherein the plurality of photodetectors are disposed in the sensor layer adjacent the frontside; a region of a second type conductivity formed in at least a portion of the sensor layer adjacent the frontside and connected to a voltage terminal for biasing the second type conductivity region at a predetermined voltage; a well of the second type conductivity formed in the sensor layer adjacent the backside; and trench isolations in the sensor layer starting at the frontside and extending beyond the depletion region of the photodetectors and to portions of the insulating laver, wherein the trench isolations include portions that do not extend to the insulating layer so as to connect the well at the backside between adjacent photodetectors; and a lining of the second type conductivity lining the trench isolations, wherein the lining electrically connects the region of the second type conductivity adjacent the frontside with the well adjacent the backside. - View Dependent Claims (2, 3, 4, 5)
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6. A method for producing a back-illuminated image sensor, comprising:
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providing a sensor layer having a frontside and a backside opposite the frontside; situating an insulating layer adjacent the backside; situating a circuit layer adjacent the frontside; providing a plurality of photodetectors of a first type conductivity for converting light incident on the backside into photo-generated charges, the photodetectors having a depletion region, wherein the plurality of photodetectors are disposed in the sensor layer adjacent the frontside; forming a region of a second type conductivity in at least a portion of the sensor layer adjacent the frontside; biasing the second type conductivity region at a predetermined voltage; forming a well of the second type conductivity in the sensor layer adjacent the backside; and providing trench isolations in the sensor layer starting at the frontside and extending beyond the depletion region of the photodetectors and to portions of the insulating layer, wherein the trench isolations include portions that do not extend to the insulating layer so as to connect the well at the backside between adjacent photodetectors; and providing a lining of the second type conductivity lining the trench isolations, wherein the lining electrically connects the region of the second type conductivity adjacent the frontside with the well adjacent the backside. - View Dependent Claims (7, 8)
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9. An image capture device, comprising:
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a lens configured to receive light; a back-illuminated image sensor including; a sensor layer having a frontside and a backside opposite the frontside; an insulating layer adjacent the backside; a circuit layer adjacent the frontside; a plurality of photodetectors of a first type conductivity for converting light from the lens incident on the backside into photo-generated charges, the photodetectors having a depletion region, wherein the plurality of photodetectors are disposed in the sensor layer adjacent the frontside; a region of a second type conductivity formed in at least a portion of the sensor layer adjacent the frontside and connected to a voltage terminal for biasing the second type conductivity region at a predetermined voltage; a well of the second type conductivity formed in the sensor layer adjacent the backside; and trench isolations in the sensor layer starting at the frontside and extending beyond the depletion region of the photodetectors and to portions of the insulating layer. wherein the trench isolations include portions that do not extend to the insulating layer so as to connect the well at the backside between adjacent photodetectors; and a lining of the second type conductivity lining the trench isolations, wherein the lining electrically connects the region of the second type conductivity adjacent the frontside with the well adjacent the backside. - View Dependent Claims (10, 11, 12, 13)
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Specification